Apparatus for measuring the volume of liquid in a tank



May 10, 193s. 4 1, M LYNSKEY 1 2,117,185

APPARATUS FOR MEASORING THE VOLUME OF LIQUID IN A TANK Filed Feb. 27,1937 3 Sheets-Sheet l Wye ai Jsqa? 1.2% ...1572/526 May 103, 1938. .1.M. LYNSKEY 2,117,185

APPARATUS FOR MEASURING THE VOLUME C-)F LIQUID IN A 'I ANK Filed Feb.27,'1957 3 sheets-sheet 2 May 10, 1193s.y

J. M. LYNSKEY APPARATUS FOR MEASURING THE VOLUME OF LIQUID IN A TANKFiled Feb. 27. 1957 5 Sheets-Sheet 5 y T/w a. WM

Patented May l0, 1938 UNITED STATES PATENT OFFICE 2,117,185 APPARATUSFOR MEASURING THE VOLUME LIQUID 1N A TANK 11 Claims.

My invention relates to an apparatus for measuring the volume of liquidin a tankand is particularly adaptedfor use in measuring the contents oflarge gasoline or other types of liquid storage tanks. There are twodistinct types of such tanks on the market, namely, (1) with a iixedroof on the top thereof and (2) another having a roof floating on thesurface of the liquid contained therein and my invention may be modifiedfor use with either type of tank.

An object of my invention is to measure the amount of liquid in eitherof such types of tanks from a point entirely without the tank therebyeliminating any possible errors due to the capillary movement of theliquid level in measuring l bobs or strips inserted from the top of thetank.

manometer to a point exterior of the ,tank at.

lwhich the displacement or immersion of such immersion member ismeasured so that the readings of the means measuring the height at whichsaid immersion member is displaced may be corrected for the actualamount of immersion of said member to obtain an indication of trueliquid level.

A further object of my invention is to provide an immersion member ofnegligible displacement area to not in any appreciable amountV aiect themeasurements.

My invention particularly relates to an apparatus for use in measuringthe amount of liquid in a type of tank having a floating roof which hasbeen extremely difficult hitherto, due to (l) variations in load on saidroof and (2) variations of stresses caused by said load on the materialof the roof, and my invention further relates to a novel method ofempirical calibration of such a load on the roof, such calibrationsrepresenting actual loadV conditions.

In the actual making of tests, I have found that with variations in loadthereon certain types of roofs rise and other types lower caused bydiffers ent designs of the roofs which bend at different points thereonunder stress and for complete accuracyr it is necessary to calibratecorrection factors for each individual tank even though they are of thesame dimension and design.

In tanks having iioating roofs at times pari ticularly when gasoline iscontained therein, gas pockets develop beneath the roof which will tendto affect the' height readings heretofore mentioned. Employing myinvention, however, these are additionally indicated and may becorrected by means usually provided to release such gases.

These and such other objects of my invention as may hereinafter appearwill be best understood from a description of the accompanying drawings,which illustrate various embodiments thereof.

In the drawings, Fig. 1 is a fragmentary vertical sectional view througha floating roof tank having my invention attached with parts oi' themechanism shown in elevation.

Fig. 2 is a fragmentary elevation of such a tank looking towards theindicating mechanism.

Fig. 3 is an enlarged detailed sectional view taken through the gaugehatch of the iioating roof and showing portions of my invention in oelevation.

Fig. 4 is a vertical sectional view similar to Fig. 1 of all portions ofmy invention shown therein, except the indicating mechanism of anembodiment of my invention applied for use on a tank having a closedroof.

Fig. 5 is a front elevation of a liquid pressure indicating scaleadapted for use in the embodiment of my invention shown in Fig. 4.

I have shown in Figs. 1-3 an embodiment of my invention adapted for usefor measuring the volume of the liquid I2 within the tank I0 having theroof I8 floating on the surface of said liquid I2 to Icompensate forvariations .in load in said roof and other conditions within said tankaffecting the liquid level, said roof being provided as 3 usual with agauge hatch which may be provided as usual with the gauge hatch tube 26.'Ihe immersion member I4 comprises a rigid tube I6 preferablyconstructed of copper or other suitable metal or rigid materialfixedlysecured to the roof I8, such as by the clamp 30 to depend a definiteamount from its point of attachment to said roof within the liquid I2,in my preferred embodiment projecting downwards through said hatch tube26 a xed distance and having a 4 lower end of substantially relativelynegligible displacement area for immersion within said liquid I2.

I also provide a Weight 22 vertically movable within said tank adaptedto abut a fixed point on said roof I8 inthe embodiment shown, the upper.end 24 of the hatch tube 26, said pointu being fixed relative to thelower end 32 of said tube, said weight comprising a portion of means,preferably operable from the point exterior of said tank atsubstantially the level of"`the base of said tank for-measuring theheight ci a pointv 24 fixed relative to the point 32 of said member I4relative to the liquid capacity height of the tank and preferablyindicate said height at substantially said point exterior of said tank.The

' point exterior of said tank at substantially the level of the base ofsaid tank is provided for reeling the lower end of said tape 40 thereonand means such as the handwheel 48 is provided to rotate said reel 44 bymeans of suitable gearing 48 to raise said weight 22 and permit saidweight 22 to lower itself and its connected cable 36 within said tankand raise the tape 40 exterior of said tank. I also provide a pointer5I! located at a lilxed point adjacent said tape 40 to indicate on saidtape scale 42 the relative height of said weight 22 and hence fixedpoint 24 of said roof within the tank.

If desired means are provided within said tank to insure that the weight22 may move in a substantially vertical path within said tank and forthis purpose in the embodiment shown, I have constructed the weight 22with the laterally pro- 'jecting arms 52 forming a cross head for said'weight and adapted to abut the upper end 24 of said tubular hatch 2t toform a fixed-point on said roof for the abutment of the weight 22thereon. The arms 52 are also provided with the vertical holes 54 toreceive the guide wires S6 projecting downwardly from suitable arms 58fixedly mounted on or adjacent said tank through said sion of saidmember Id within the liquid I2 will now be described, which as statedhitherto, is identical for either embodiment, with the exception of thescale on the manometer or glass gauge. As stated hitherto, I preferablymeasure the depth of immersion of said tube Id within said liquid bytransmitting the liquid pressure in said liquid at the depth of liquidpenetration of the lower end 'of said tube to indicate on a suitablemanometer able scale 84, shown in Fig. 2. As stated hitherto, said meanspreferably takes the form of an indicating manometer modified to beparticularly desirable for this purpose, said manometer broadlyspeaking, comprising a modified U-tube containing indicating liquid 66having one leg thereof connected to the lower end of said rigid tube I 4and being thus open to atmosphere above the liquid level I6 and theother indicating leg having an upper end also open to the atmosphere sothat the height of liquid in the leg comprising the glass gauge 68 orindicating leg may indicate the actual diierences in liquid pressureonly, due to the varying depths of penetration of the lower end of thetube I4 below the liquid level IB. One leg of said U-tube comprises arelatively large reservoir 10, preferably having glass walls forcontaining indicating liquid CI and for reasons of accuracy. Ipreferably employ an indicating. liquid of substantially the samespecific gravity as that of the liquid in the tank. I provide tubularmeans 12 for connecting the oil reservoir with said rigid tube I4 havinga exible portion 14 within said tank to ex to compensate for the raisingor lowering of said roof I8. In the embodiment of my invention shown, Ipreferably employ a rigid metal pipe leading from said reservoir 1l andterminating at a point-above said tank to whichr the flexible portion 14may be attached which iexible portion 14 has the other end thereofattached to the rigid tube I4. To transmit the liquid pressure throughsaid tube 12 by means of substantially completely compressed air, Iprovide the air pump 18 connected to said tubular means 12 provided withthe usual piston and handle for this purpose and to release the thusbuilt up air pressure within the tube 12 between the reservoir 10 andtube I4 I provide an air vent 18 connected to said tube and comprising astandard type oi handle operated air pressure valve. As stated hitherto,the U-leg 68 or manometer comprises a vertically extending transparent,preferably glass gauge 88 connected to the bottom of said reservoir 10and I provide a measuring strip 18 vertically adjustable relative tosaid glass gauge by means of the adjusting set screw 80. The strip 19 isvertically adjustable not only for calibration purposes, but also toprovide at all times a true zero reading, regardless of shrinkage orexpansion in the liquid 66. A zero mark 82 is provided on the scale 64on said strip 19.

In use the air vent 18 is opened and the scale 54 is vertically adjustedby means of the adjusting set screw Bil to the zero mark 82. Assumingthat-'the liquid I2 is to be measured in the tank I0 with no load on theroof or no other adverse conditions, such as gas pockets affecting theheight of the roof, the lower end 32 of the tube It will be immersed anunvarying amount from .the roof within the liquid I2. The air vent 18may then be closed and by means of the air pump 16 air may be pumpedWithin the tube 12 up to its substantial limit of compressibility tocause it to transmit the liquid pressure in said liquid I2 at the thendepth of liquid penetration of the lower end 32 of said tube It withinsaid liquid I2 to indicate the depth of immersion of said tube It withinsaid liquid and a mark 84 may be madeon said scale above said zero 82 toindicate the standard depth of immersion of said tube I4 Within theliquid I2 for no load on the roof or any adverse conditions.

As stated hitherto, with tanks with oating roofs variations in the depthof immersion of said tube III in said liquid I2 take place withvariations of load on said roof and corresponding correction factors tocorrect the actual measurement on the tape scale 42 may be calibrated onsaid scale B4 for variations in load on said roof I8. The roof may begradually loaded with Water or other substance and when the4 pointer 50showsl 1/8" difference on the tape 40, a mark is scribed on the strip'19to form the scale 64 on said strip which is stamped 1A". As the weighton the roof is increased and when the scale 42 on tape 4D shows adiilerence of $44" another mark is scribed in line with the height ofliquid in said gauge 66 higher up on the strip 19 to form another scalemark on said strip 19. Continued marks are successively scribed on saidstrip 18 opposite the u height of liquid 86 in glass gauge 88corresponding to V" difference in readings of the scale 42 on the tape40 against the pointer 50 to form the scale 54 on said strip 19 untilthe roof r' (il) is fully loaded with water. Although the scale 42 showsuniform graduations for i6" variations in height on said tape 40, thegraduations on the scale 64 will be uneven a'nd the distance betweensuccessive graduations on the scale will vary. This variation is causedby difference in the design oi the roof itself which aiects itsdisplacement and its bending under varying degrees of load which mayeven vary under different conditions of installation even ifroofs of thesame size and design be employed.

After the scale 64 has once been calibrated on the strip 19 to employ mydevice to obtain an accurate volumetric indication of the volume ofliquid i2 within the tank I compensated for varying degrees of load, aheight reading on the tape scale 42 is made, the liquid pressureproportionate to the depth of penetration of the end I2 of the tube I4within the liquid is transmitted in the manner explained, to the glassgauge 68, namely, by initially releasing the air pressure in the tubeand building up a transmitting pressure in said tube by means o! thepump I8, and the level of the liquid 66 in the glass gauge 6B may beread od on the scale 64 and with a load on the roof will vary from thenormal level mark 84 in amounts proportionate to said load and thecorrection factors to be applied to the height measurement 42 forvariations in said load may be read off said scale 54 for any outagemeasurement. In the embodiment shown, the scales 42 and 64 have beenconstructed for outage measurement and thus, to obtain the volume ofliquid left in the tank it will be necessary to subtract the outagemeasurement from the total tank capacity.

As stated, the measuring apparatus may be designed to measure either theinnage or outage of the tank as shown. For example, assuming that thetank is filled to its full liquid capacity, with no extra load on thetop of the roof, or no gas formed beneath the roof. The tape 40 at thepointer 50 would read zero, and the liquid level in the glass tube 68would be level with the line 84cm the metal strip 19,. 'Therefore, nooutage is indicated. The liquid volume is the full capacity of the tank.Again assuming that a portion of the liquid has been removed from thefull tank, and rain water is on the top of the roof, the measurement ofthe liquid volume in -the tank is obtained as follows: The weight 22 islowered until the arm 52 on the weight 22 rests on the top of gaugehatch 24. The measurement on the steel tape 40 at the pointer 50 reads10 feet. The liquid in the glass tube 63 is level with the line marked1V2 inches.` on the metal strip 19this being the type roof which riseslwhen weight is added to the top of it. The 11/2 inches indicated on themetal strip 'I9 is added to the tape measurement at the pointer'50,giving a corrected reading of 10 feet 15/2 inches outage. This,subtracted from the height of the tank, which I will assume is feet,gives an innage of 35 feet minus 10 feet 1% inches, lwhich equals 24feet 10i/2 innage.

Explanation of how by reversingthe steel tape 40. the innage could beobtained: For example, I shall assume that the same conditions exist, as

mentioned in the previous explanation to obtain the outage. The tape atpointer ill in this method reads 35 feet instead of zero when the tankis illled to capacity with no extra .load on top of the roof or no gasformed beneath it. Consequently, the liquid volume is the full capacityof the tank. as indicated by the measurement 35 feet on the tape 4'0 atpointer 50, again assuming that the same amount of liquid has beenremoved from the tank, and the same amount of rain water being on thetop of the roof. 'I'he weight 22 is lowered until the arms 52 on theweight 22 rest on the top of gauge hatch 24. The measurement on thesteel tape 42 at the pointer l0 will now read 25 feet, the weight on theroof being the same in both examples. The

11/2 inches indicated on the metal strip I9 is deducted from themeasurement 25 feet. giving an innage of 24 feet 10%4 inches-themeasurement obtained in both examples being identical.

My explanation as listed above, covering the floating roof type tank,also applies to the stationary roof type tank, drawings Fig. 4, with theiollowing exceptions: When the steel tape 40. Fig. 2, is installed foroutage measurements, the indicated correction on metal strip 62, Fig. 5,is subtracted from the measurement on steel tape 40 at pointer 50, Fig.2. When the tape 40 is yreversed and installed i'or innage measurement,

the indicated correction is added to the measurement on steel tape 4u atpointer 5l, Fig. 2.

If the height of liquid 66 in said gauge il is below the standard mark84 for the standard amount of immersion of said tube I4 within theliquid I2 under normal conditions, it provides an immediate indicationof gas pockets below the roof which may be discharged through suitable'vents or other means normally provided for this purpose in the roof I8.

In the embodiment of my invention shown in Figs. 4 and 5 for measuringthe volume of liquid in a tank having the fixed roof or stationary topI8', the cable 38 carrying the weight 22 may be lowered through themanhole 80 usually provided in said top I8' and similar weighting means00 and supporting wires 56 may be provided to maintain the path ofmovement of said weight 22 in a vertical line within said liquid I2. Inthis ernbodiment of my invention, the tube I4 may be directly attachedto the weight 22, such as by the strap 20 and has the lower end 32thereof preferably in line with the lower end 2l of said weight 22 sothat when the weight 22 and attached tube i4 strike the surface of theliquid an indication will be-immediately made thereof by the height ofliquid 66 in the gauge glass 6l. In this instance, however, the scale 64is calibrated directly in amounts proportionate to the depth ofimmersion of said tube i4 within the liquid I2 to give equally spacedcorrection factors directly proportionate thereto to be .applied to thereading 'on the tape scale 42 to give the actual height of liquid in thetank relatively to the capacity height Vof said tank for calculation ofthe volume of liquid then in said tank.

It is understood that my invention is not limited to the variousembodiments shown or methods described and that various deviations maybe made therefrom without departing from the spirit and scope of theappended claims.

What I claim is: 4

1. A device for use in measuring the volume of a liquid within a tankhaving a roof floating on the surface of said liquid including means tocompensate for variations in-the load on said roof and other conditionswithin said tank aiIecting the liquid level, comprising an immersionmember oi unvarying length from a fixed point u on said roof and havinga substantially relatively negligible displacement area projectingslightly below the liquid level in said tank, means operable from apoint exterior of said tank at substantially the level of the base ofsaid tank for measuring the height of a point of said roof fixedrelatively to said member relative to the liquid capacity height of saidtank and indicate it at substantially said point exterior of said tankand means for measuring the liquid pressure in said liquid at the depthof liquid penetration of the lower end of said member to indicate thedepth of immersion of said member within said liquid thereby indicatingat substantially said point exterlor of said tank a calibratedcorrection of said fixed point height measurement for calculation of theamount of liquid in said tank.

2. A device for use in measuring the volume of a liquid within a tankhaving a rooi iioating on the surface of said liquid including means tocompensate for variations in the load on said roof and other conditionswithin said tank affecting the liquid level, comprising an immersionmember of unvarying length from a iixed point on Said roof, means formeasuring the height of a point of said roof lxed relatively to saidmember relative to the liquid capacity height of said tank and means formeasuring the depth of immersion of said member within said liquidthereby indicating a calibrated correction of said iixed point heightmeasurement for calculation of the amount of liquid in said tank.

3. A device for use in measuring the volume of a liquid within a tankhaving a roof iioating on the surface of said liquid including means tocompensate for variations in the load on said roof and other conditionswithin said tank aiecting the liquid level, comprising an immersionmember of unvarying length from a iixed point on said roof, means formeasuring the height of a point of said roof fixed relatively to saidmember relative to the liquid capacity height of said tank and means formeasuring the liquid pressure in' said liquid at the depth of liquidpenetration of the lower end of said member to indicate the depth ofimmersion of said member within said liquid thereby indicating acalibrated correction of said fixed point height measurement forcalculation of the amount of liquid in said tank.

4. A device for use in measuring the volume of a liquid within a tankhaving a roof floating on the surface of said liquid including means tocompensate for variations in the load on said roof and other conditionswithin said tank affecting the liquid level, said roof having a gaugehatch, comprising a rigid tube fixedly secured to said roof andprojecting downwardly through said hatch a fixed distance within saidtank and a weight vertically oscillatable within said tank adapted toabut a fixed point on said roof relative to the lower lend of said tube,guide means mounted above said tank, a cable supporting said weightpassing over said guide means and extending vertically downwardlyexteriorly of said tank, a tape connected to the outer end of said cableand having scale indicia thereon indicative of the height of said roofabutting weight within said tank, a reel for reeling the lower end ofsaid tape thereon, means to rotate said reel to raise said connectedtape, cable and weight within said tank and to permit said weight tolower said connected tape and cable within said tank, a pointer locatedat a fixed point adjacent said reel to indicate the height of saidweight and hence roof on said tape scale, a reservoir fon containingindicating liquid of substantially the specic gravity of the liquid insaid tank, tubular means connecting said reservoir with said rigid tubehaving a exible portion within said tank to ex to compensate for raisingand lowering of said roof, an air pump connected to said tubular means,an air vent connected to said tubular means, a vertically extendinggauge. glass connected to the bottom of said reservoir, and a measuringstrip vertically adjustable relative to said gauge glass having aprecalibrated scale of correction factors proportionate to varying loadson said roof to apply to the roof height tape scale readings to correctthem for varying loads on said roof.

5. A device for use in measuring the volume of a liquid within a tankhaving a roof floating on the surface of said liquid including means tocompensate for variations in the load on said rooi' and other conditionswithin said tank aiecting the liquid level, comprising a rigid tubexedly secured to said roof and projecting downwardly a iixed distancewithin said tank and a weight vertically oscillatable within said tankadapted to abut a i'lxed point on said roof relative to the lower end ofsaid tube,l guide means mounted above said tank, a cable supporting saidweight passing over said guide means and extending vertically downwardlyexteriorly of said tank, indicating means adapted to function with saidcable to indicate the height of said roof abutting weight within saidtank and an indicating manometer connected to said tube to measurel theliquid pressure in said liquid at the depth of liquid penetration of thelower end of said tube thereby indicating the depth of immersionthereof, said manometer having a precalibrated scale of correctionfactors proportionate to varying loads on said roof to apply toindications of said indicating means to correct them for varying loadson said roof.

6. A device for use in measuring the volume of a liquid within a tankcomprising a rigid tube, a weight vertically oscillatable within saidtank and having said tube iixedly secured thereto. guide means mountedabove said tank, a cable supporting said Weight passing over said guidemeans and extending vertically downwardly exteriorly of said tank, atape connected to the outer end of said cable and having scale indiciathereon indicative oi the height of said weight within said tank, a reelfor reeling the lower end of said tape thereon, means to rotate saidreel to raise said connected tube, cable and weight within said tank andto permit said weight to lower said connected tube and cable within saidtank, a. pointer located at a iixed point adjacent said reel to indicatethe height of said weight on said tape scale, a reservoir for containingindicating liquid of substantially the specific gravity of the liquid insaid tank, tubular means connecting said reservoir with said rigid tubehaving a flexible portion within said tank, an air pump connected tosaid tubular means, an air vent connected to said tubular means, avertically extending gauge glass connected to the bottom of saidreservoir and a measuring strip vertically adjustable relative to saidgauge glass having a scale indicative of the depth of immersion of saidrigid tube'within said liquid whereby the readings on said tape scalemay be corrected by the readings on said measuring strip to obtain anindication of true liquid level.

7. A device for use in measuring the volume of a liquid within a tank,comprising a rigid tube 'having a lower end of a substantiallyrelatively negligible displacement area for immersion within saidliquid, a weight vertically oscillatable within said tank and havingsaid tube xedly secured thereto, guide means mounted above said tank, acable supporting said weight passing over said guide means and extendingvertically downwardly exteriorly of said tank, weighting means locatedbelow the liquid level in said tank, guide means for said weightconnected to said weighting means to maintain the path of oscillation ofsaid weight within said tank in a vertical line, indicating means atsubstantially the level of the base of said tank adapted to functionwith said cable to indicate the height of said weight within said tankand an indicating manometer, connected to said tube to measure theliquid pressure in` said liquid at the depth of liquid penetration ofthe lower end of said tube, having a scale indicative of the depth ofimmersion oi said rigid tube within said liquid, said manometer beinglocated substantially adjacent said indieating means whereby the readingof said first indicating means may be corrected by the reading on saidmanometer scale to obtain an indication of true liquid level.

8. A device for use in measuring the volume of a liquid within a tank,comprising a rigid tube, a weight'vertically oscillatable within saidtank and having said tube xedly secured thereto,l

guide means mounted above said tank, a cable supporting said Weightpassing over said guide means and extending vertically downwardlyexteriorly of said tank, indicating means adapted to function with saidcable to indicate the height of said weight within said tank and anindicating manometer, connected to said tube to measure the liquidpressure in said liquid at the depth of liquid penetration of the lowerend of said tube, having a"scale indicative of the depth of immersion ofsaid rigid tube within said liquid whereby the reading of said firstindicating means may be corrected by the reading on said manometer scaleto obtain an indication of true liquid level.

9. lA device for use in measuring the contents of a tank, comprising animmersion member, means for effecting immersion of said member below theliquid level in said tank, means for measuring the height of a point onsaid nrst means movable relative to the liquid capacity height of saidtank and bearing a fixed relationship to said member in its immersedmeasuring position, and means `for measuring the liquid pressure in saidliquid at the depth of immersion of the lower end of said member toindicate the depth of immersion of said member within said liquidwhereby the readings of said ilrst measuring means may be corrected forimmersion of said member to obtain an indication of true liquid level.

10. -A device for use in measuring the contents of a tank, comprising animmersion member having a portion having a substantially relativelynegligible liquid displacement area, means for eecting immersion of saidmember slightly below the liquid level in said tank, means for measuringthe height of a point on said first means movable relative to the liquidcapacity height of said tank and bearing a iixed relationship to saidmember in its immersed measuring position, and means for measuring theliquid pressure in said liquid at the depth of immersion of the lowerend of said member to indicate the depth of.

immersion of said member within said liquid whereby the readings of saidfirst measuring means may be corrected for immersion of said member toobtain an indication of true liquid level.

l1. A device for use in measuring the contents of a tank, comprising animmersion member, means for eiecting immersion of said member below theliquid level in said tank, means operable from a point exterior of saidtank at substantially the level of the base oi. said tank for measuringthe height of a point on said first means movable relative to the liquidcapacity height of said tank and bearing a xed relationshipl to saidmember in its immersed measuring position, and means for measuring theliquid pressure in said liquid at the depth of immersion of the lowerend of said member to indicate the depth oi' immersion of said memberwithin said liquid at substantially said point whereby the readings ofsaid rst measuring means may be corrected for immersion of said memberto obtain' an indication o1 true liquid level.

JOSEPH M. LYNSKEY.

